ABSTRACT SIMmersion LLC, in collaboration with Drs. Galupo, Schmidt, Matsuno, Bettergarcia, Hernndez, Mastroleo, and Kukucka, is proposing to develop and evaluate Training Trans-Affirmative Communication Skills (TTACS), a suite of conversation simulations that provide mental health care providers with experience working with Transgender and gender nonconforming (TGNC) individuals. The proposed product utilizes SIMmersion?s PeopleSim conversation software that has already been proven to improve clinical skills in a variety of areas. The diverse development team, which includes TGNC individuals and people of color at every level of input (including Key Personnel, Expert Panel, Actors, Focus Group, and Community Partners) will design and create four modules within TTACS that allow mental health care clinicians and clinicians-in-training to develop gender- affirming communication skills for clients with diverse needs. TTACS modules will focus on Intake, Traditional Needs, High-Risk Needs, and Social and Physical Transitions, and the fictional characters in the training will be represented by a diverse group of actors from the trans community. The proposed TTACS provides an innovative response to the call for training initiatives for implementing the American Psychological Association (APA) guidelines for trans-affirmative, culturally competent, and developmentally appropriate care into psychological practice for TGNC people. During Phase I of the fast-track research, the team will evaluate the feasibility of using a PeopleSim training to improve clinicians? skills at meeting the needs of TGNC individuals. The team will create a design plan for the entire TTACS system (Aim 1), develop the Intake module (Aim 2), conduct a within-group pre-post knowledge assessment with clinicians-in-training (Aim 3a), and a focus group discussion with key decision makers and supervisors (Aim 3b). Success in Phase I will lead directly into Phase II development of the remaining TTACS modules (Aim 1) and the development of Standardized Patient Scenarios and checklists for evaluating the skills of clinicians-in-training working with TGNC clients (Aim 2), which will be used in a Randomized Controlled Trial (Aim 3) with 100 students enrolled in clinical and counseling psychology graduate programs. The team plans to begin commercializing TTACS (Aim 4) to university programs, independent training organizations, health care centers, and professional organizations, starting with the individuals and organizations that provided letters of support. If successful, the proposed research could help reduce the patterns of mistreatment, discrimination, and physical and mental health disparities TGNC individuals experience when they seek mental health care.